1. Related Applications
This application is an improvement of our U.S. Pat. No. 4,875,464, issued 24 October 1989 for a "Clean Burning Gas Log Burner System".
2. Field of the Invention
The present invention relates to efficient gas burners for burning natural gas, manufactured gas and propane gaseous fuels. More particularly, the present invention relates to an efficient burner system for burning gaseous fuels in a manner which provides decorative flames and decorative embers which simulate wood burning.
3. Description of the Prior Art
Gas logs are usually made of a fire resistant ceramic material as is well known. Heretofore when a gas burner system was employed below such prior art decorative gas logs, the gas flame that was directed against the gas logs was cooled so as to produce a highly inefficient and dirty yellow flame. In our U.S. Pat. No. 4,875,464 there is shown and described a highly efficient gas burner system wherein the flame from the gas burner is isolated and directed away from impinging on the gas logs which act as a heat damper or heat sink, thus, creating excessive soot and carbon monoxide (CO). In the preferred embodiment of this prior art invention an inverted U shaped shield is mounted over the gas burner and provided with horizontal openings in the U shaped shield so as to guide and deflect the gas flames away from the decorative gas logs and to produce a clean burning gas log burner system.
Heretofore it was known that gas burners or gas nozzles could be buried below a level of sand or vermiculite. These burner systems were heretofore referred to as sand pan burners which dispersed the gases through the fireproof material and permitted the gas permeating through the porous material to ignite upon entering the atmosphere so as to present an orange or yellow dispersed flame over a large area or bed of material. As will be explained in more detail hereinafter expanded fireproof material has been sprinkled over the sand pan devices so that the gas burning over the dispersed area burns through the added expanded fireproof material and produces an orange color flame in the expanded fireproof material which simulated to some extent hot ashes in a fireplace. These prior art sand pan burners are known to produce carbon monoxide levels in excess of 200 parts per million (ppm) and excessive amounts of carbon and soot.
Presently the American National Standards Institute (ANSI) Emission and Safety Standards Z-21.50 (1986), which has been adopted by the American Gas Institute, only permits 200 parts per million carbon monoxide when burning natural gas or liquified petroleum fuels. Accordingly, the prior sand pan devices have exceeded the accepted levels of the American National Standards Institute and the American Gas Institute, thus, creating a pollution problem which has resulted in some manufacturers attempting to modify the standard so as to increase the pollution in the atmosphere.
When the prior art burner systems for artificial decorative logs and sand pan type burners are incorporated into pre-fabricated fireplaces or existing masonry fireplaces, they must meet the ANSI emission standards which have been adapted by the American Gas Institute. Accordingly, it would be desirable to provide a clean burning gas burner system for glowing embers and for gas logs which meet the present ANSI emission standards.
There is a present and long felt need for such gas log and glowing ember burner systems which will burn clean and which very closely simulate the natural flames produced by burning wood logs. Therefore it is desirable to produce a reliable and efficient gas log and glowing ember burner system which produces the desirable yellow and orange decorative flames that closely simulate burning wood logs and which provide efficient usable heat and still meets the EPA regulations and the ANSI emissions and safety standards.